What is UF foam?
UF foam stands for urea-formaldehyde foam. It was injected as a liquid foam into the cavity, where it hardened. In the seventies and eighties, it was a widely used method to insulate existing cavity walls.
Disadvantages of UF foam
In practice, UF foam has shown several disadvantages, which is why it is hardly used today.
- The foam can shrink over time, creating gaps and unprotected areas in the cavity.
- It can crumble and settle, reducing its insulating value.
- Formaldehyde can be released during application and curing.
- It absorbs moisture more easily than modern cavity wall insulation.
How do I know if there's UF foam in my cavity wall?
If your home was insulated after construction between approximately 1970 and 1985, it might contain UF foam. You can often still see the sealed drill holes from that time in the mortar joints. You can gain certainty with a cavity inspection, for example, with a camera through a small hole.
UF foam or glass wool: the comparison
Modern cavity wall insulation, such as blown-in glass wool, does not have the disadvantages of UF foam. Glass wool does not shrink, is water-repellent and vapour-permeable, and does not release formaldehyde. Greenisolatie therefore uses glass wool in cavity walls.
- Shrinkage: UF foam can shrink, glass wool does not with correct filling
- Moisture: glass wool is water-repellent
- Fire safety: glass wool is non-combustible
- Long-term performance: glass wool retains its insulating value
What can you do with old UF foam insulation?
If there's UF foam in your cavity wall, it often insulates less effectively than you might think. Whether improvement is possible depends on the condition of the foam and the remaining space in the cavity. Our advisor will assess this free of charge at your home and provide honest advice on the possibilities.
Frequently asked questions
Is UF foam dangerous?
Formaldehyde is primarily released during application and curing. For foam that has been in the cavity wall for decades, this has usually significantly decreased. The main problem is often that the insulating value has diminished due to shrinkage and crumbling.
Can I insulate over UF foam?
That depends on the condition of the foam and the space in the cavity. Our advisor will assess this at your home.
Which material does Greenisolatie use in cavity walls?
We insulate cavity walls with blown-in glass wool.